import type { FocusRow } from './types.js';
/** INSERT a viewport. Throws on UNIQUE(node_id) if `node_id` already occupies
 *  another focus (or on PK conflict if `focus_id` exists) — by design. */
export declare function openFocusRow(focus_id: string, pane: string | null, session: string | null, node_id: string): void;
/** Hot-swap a focus's occupant — single-statement UPDATE. Respects
 *  UNIQUE(node_id): if `node_id` already occupies ANOTHER focus this throws
 *  (correct — vacate-first is placement.focus()'s job, not this setter's). */
export declare function setFocusOccupant(focus_id: string, node_id: string): void;
/** Re-point a viewer row's durable pane + its derived session cache after the
 *  pane moves. Single-statement UPDATE. */
export declare function setFocusPane(focus_id: string, pane: string | null, session: string | null): void;
/** DELETE a viewport. */
export declare function closeFocusRow(focus_id: string): void;
/** The focus a node occupies (≤1, UNIQUE node_id), or null. */
export declare function getFocusByNode(node_id: string): FocusRow | null;
/** The focus realized by a given pane (`%id`), or null. */
export declare function getFocusByPane(pane: string): FocusRow | null;
/** A focus by its stable id, or null. Used by placement to read a row back by id
 *  after openFocusRow registers a viewer. */
export declare function getFocusById(focus_id: string): FocusRow | null;
/** Every focus row, ordered by id. */
export declare function listFocuses(): FocusRow[];